A few times each year the sky seems to fill with fluttering termites, but not all of the termites get to fly. The colony lets a few grow wings and strike out into the world. A rare time when termites act as individuals. These fliers (called alates) are just for colony reproduction. They seek to find a mate and start a new nest of their own. Just like most of we do. As many as a quarter to a third of the colony leave this way over several flights each year. By flying away and starting out as just two termites, the new colony can avoid the hitch-hikers and parasites of the old one. Flight also helps them find suitable new food (easier on the wing than in the tunnel perhaps?) that might be rare, hard to find or widely dispersed. Whatever the reason, it works. Termites have been doing this for much longer than a hundred million years, so it must be working.

Here's a (rather poor quality) flash video of winged termites from the Internet Archive.